Vented Valve Cap

ABSTRACT

A fuel cap is described as having a top assembly and a bottom assembly slidably engaged with, and concentric to, the top assembly. The top assembly having a cap cover and a cylindrical cap body concentric with and protruding substantially perpendicularly from, an underside surface of the cap cover. The bottom assembly having a vacuum valve operatively coupled with a valve body. A wire-form keeper may slidably secure the bottom assembly to the top assembly. A pressure spring may impart a force that biases said bottom assembly away from said top assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/979,074, filed on Dec. 22, 2015, which in turn claims priority toU.S. Provisional Patent Application No. 62/096,858, filed on Dec. 25,2014, and 62/119,331, filed on Feb. 23, 2015, each entitled “VentedValve Cap” by Jeffrey Alan Ayers et al. Each application is herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to the field of fluid tanks; moreparticularly, to vented valve caps for use with fluid tanks.

BACKGROUND

Various types of fuels may be stored in remote, portable, ortransportable tanks to facilitate point of use refueling. Examples ofsuch applications include, without limitation, construction andagriculture. These fuels may include, for example, diesel, gasoline, andkerosene. Often, these types of tanks are not permanent installations,but rather, are meant to be moveable. With these tanks exists a need toseal the tank, while permitting quick and easy fluid removal andreplacement. Further, to account for pressure changes that result from achange in fuel volume within the tank, a need further exists to vent thetank.

As will be appreciated by those of ordinary skill in the art, the volumeof fuel within a tank can fluctuate over time due to a number offactors, including, for example, fuel being syphoned off (e.g., used tofuel a device), evaporation of the fuel, as well thermal expansion,which may be due to ambient temperature changes. That is, changes intemperature can cause the fuel to expand or contract, thus changing itsvolume. It is therefore advantageous to counter pressure changes using,for example, a vented fill cap.

Vented fill caps serve two general purposes: (1) to seal the tank toprevent contaminant ingression and evaporative fuel loss; and (2) toprovide pressure equalization between the interior of the tank and theatmosphere (i.e., the air/gas external to the tank). Failure to providepressure equalization between the interior of the tank and theatmosphere when internal tank pressure increases and/or when a vacuum iscreated can result in destruction of the tank (e.g., due to excesspressure or vacuum). Thus, what is needed is an improved vented fill capthat seals the tank, while permitting for pressure equalization.

SUMMARY OF THE INVENTION

The present invention is directed to a vented cap for use with, interalia, fuel tanks.

According to a first aspect, a venting apparatus comprises: a cap coverhaving a cylindrical cap body concentric with, and protrudingsubstantially perpendicularly from, an underside surface of the capcover; a bottom assembly slidably engaged with, and concentric to, thecap cover, wherein the bottom assembly is sized and shaped to at leastpartially reside within the cylindrical cap body, the bottom assemblyhaving a vacuum valve slidably engaged with a valve body, wherein thevacuum valve and the valve body are arranged substantially concentric toone another, the vacuum valve being moveable between a first positionand a second position, wherein the vacuum valve prevents flow throughthe valve body in the first position and permits flow through the valvebody in the second position; a vacuum spring to bias the vacuum valve inthe first position; and a pressure spring residing at least partiallywithin each of the valve body portion and the cylindrical cap body,wherein the pressure spring is configured to impart a force that biasessaid bottom assembly away from said cap cover.

According to a second aspect, a fuel cap comprises: a top assemblyhaving a cap cover and a cylindrical cap body, the cylindrical cap bodyprotruding substantially perpendicularly from an underside surface ofthe cap cover; a bottom assembly slidably engaged with, and concentricto, the top assembly, the bottom assembly having a vacuum valveoperatively coupled with a valve body; a keeper device to slidablysecure the bottom assembly to the top assembly, wherein the bottomassembly is sized and shaped to at least partially reside within thecylindrical cap body; and a pressure spring to impart a force thatbiases said bottom assembly away from said top assembly.

According to a third aspect, a venting apparatus comprises: a cap cover,the cap cover having a cap cover and a cylindrical cap body, thecylindrical cap body protruding substantially perpendicularly from anunderside surface of the cap cover; a bottom assembly slidably engagedwith, and concentric to, the cap cover, the bottom assembly having avacuum valve operatively coupled with a valve body, wherein the valvebody comprises a cylindrical valve body portion, the cylindrical valvebody portion sized and shaped to reside at least partially within thecylindrical cap body; and a pressure spring, the pressure springresiding at least partially within each of the cylindrical valve bodyportion and the cylindrical cap body, wherein the pressure spring isconfigured to impart a force that biases said bottom assembly away fromsaid cap cover.

According to a fourth aspect, a venting apparatus for managing flowthrough a fill cap base comprises: a top assembly, the top assemblyhaving a cap cover and a cylindrical cap body concentric with, andprotruding substantially perpendicularly from, an underside surface ofthe cap cover; a bottom assembly slidably engaged with, and concentricto, the top assembly, the bottom assembly having a vacuum valveoperatively coupled with a valve body, wherein the vacuum valvecomprises a vacuum base and a vacuum stem perpendicularly positioned onsaid vacuum base, wherein the valve body comprises (1) a cylindricalvalve body portion having a first vent hole and (2) a valve base at afirst end of said cylindrical valve body portion, the valve base havinga second vent hole and a through hole configured to receive the vacuumstem, wherein the vacuum base and the valve base are arrangedsubstantially concentric and parallel to one another, the vacuum basebeing moveable between a first position and a second position, whereinthe vacuum base prevents flow through the second vent hole in the firstposition and permits flow through the second vent hole in the secondposition, the vacuum base being biased in the first position by a vacuumspring; and a pressure spring, the pressure spring residing at leastpartially within each of the cylindrical valve body portion and thecylindrical cap body, wherein the pressure spring is configured toimpart a force that biases said bottom assembly away from said topassembly.

In certain aspects, a wire-form keeper engages said cylindrical cap bodyand said cylindrical valve body portion, thereby slidably securing thebottom assembly to the top assembly.

In certain aspects, the cylindrical valve body portion comprises a ribat a second end of said cylindrical valve body portion, the ribextending along the circumference of the second end of said cylindricalvalve body portion.

In certain aspects, the cylindrical valve body portion comprises a slotand the wire-form keeper comprises a keeper indentation, the keeperindentation being configured to pass through the slot and to engage therib.

In certain aspects, the top assembly further comprises a securing tabconfigured to engage a fill cap base.

In certain aspects, the pressure spring is configured to impart asealing force that forms a seal between the bottom assembly and the fillcap base when the top assembly engages a fill cap base.

In certain aspects, the bottom assembly is configured to move towardsaid top assembly when a positive pressure at the fill cap baseovercomes the sealing force, thereby breaking a seal between the bottomassembly and the fill cap base.

In certain aspects, the vacuum base moves to the second position when anegative pressure at the fill cap base overcomes the vacuum spring'sforce, thereby permitting flow through the first vent hole and thesecond vent hole.

In certain aspects, a pressure gasket is positioned on the valve base,the pressure gasket configured to form an airtight seal between thevalve base and a fill cap base.

In certain aspects, a vacuum gasket is positioned on the vacuum base,the vacuum gasket configured to form an airtight seal between the vacuumbase and the valve base.

In certain aspects, a stability shim is positioned on the undersidesurface of the cap cover, whereby the stability shim restricts lateralmovement of the venting apparatus when installed upon a fill cap base.

In certain aspects, the stability shim is fabricated from a fuelresistant flexible material.

In certain aspects, the vacuum stem passes through the vacuum spring,the vacuum stem being configured to secure an end of the vacuum springat the vacuum stem's distal end.

DESCRIPTION OF THE DRAWINGS

These and other advantages of the present invention will be readilyunderstood with the reference to the following specifications andattached drawings, where like reference numbers refer to likestructures. The figures are not necessarily to scale, emphasis isinstead placed upon illustrating the principles of the devices, systems,and methods described herein.

FIG. 1a illustrates an assembly view of a vented valve cap in accordancewith an aspect of the present invention.

FIG. 1b illustrates a cross-sectional side view of an assembled ventedvalve cap.

FIG. 1c illustrates an assembly view of the vented valve cap's topassembly and bottom assembly.

FIG. 1d illustrates an exploded view of the wire-form keeper when thevented valve cap is assembled.

FIG. 1e illustrates a cross-sectional side view of an assembled ventedvalve cap having a stability shim.

FIG. 1f illustrates a perspective view of the underside of the topassembly having a stability shim, with the wire-form keeper engaged.

FIG. 1g illustrates an assembly view of a vented valve cap having astability shim in accordance with an aspect of the present invention.

FIG. 2a illustrates a top plan view of the topside of the top assembly.

FIG. 2b illustrates a top plan view of the underside of the topassembly.

FIG. 2c illustrates a perspective view of the underside of the topassembly with the wire-form keeper disengaged.

FIG. 2d illustrates a perspective view of the underside of the topassembly with the wire-form keeper engaged.

FIG. 3a illustrates a perspective view of the topside of the bottomassembly.

FIG. 3b illustrates a top plan view of the topside of the bottomassembly.

FIG. 3c illustrates a cross-sectional side view of the bottom assembly.

FIG. 4a illustrates a top plan view of the topside of a valve body ofthe bottom assembly.

FIG. 4b illustrates a perspective view of the valve body and pressuregasket of the bottom assembly.

FIG. 5a illustrates a perspective view of the vacuum valve and vacuumgasket of the bottom assembly.

FIG. 5b illustrates a side view of the vacuum valve with the vacuumgasket installed.

FIG. 5c illustrates a top plan view of the vacuum valve with the vacuumgasket installed.

FIG. 6a illustrates a perspective view of the valve body and vacuumvalve.

FIG. 6b illustrates a top plan view of the valve body with the vacuumvalve installed.

FIG. 6c illustrates a side view of the valve body with the vacuum valveinstalled.

FIG. 6d illustrates a cross-sectional side view of the valve body withthe vacuum valve installed.

FIG. 7a illustrates a top plan view of the valve body with the vacuumvalve and vacuum spring installed.

FIG. 7b illustrates an exemplary process by which a vacuum spring may beinstalled in the bottom assembly.

FIGS. 7c and 7d illustrate an exemplary arrangement for securing thevacuum spring using an e-clip.

FIG. 8a illustrates a vented valve cap coupled to a tank under pressureequalization.

FIG. 8b illustrates a vented valve cap coupled to a tank having apositive pressure.

FIG. 8c illustrates a vented valve cap coupled to a tank having anegative pressure (vacuum).

FIG. 9a illustrates an inner cap having a stability lever.

FIG. 9b illustrates an example assembly view of a vented valve caphaving an inner cap having a stability lever.

FIGS. 9c and 9d illustrate perspective views of the vented valve cap ofFIG. 9 b.

FIG. 10a illustrates an inner cap having a set of stability levers.

FIG. 10b illustrates an example assembly view of a vented valve caphaving an inner cap having a set of stability levers.

FIGS. 10c and 10d illustrate perspective views of the vented valve capof FIG. 10 b.

FIG. 11a illustrates a wave spring stability shim.

FIG. 11b illustrates an example assembly view of a vented valve caphaving a wave spring stability shim.

FIGS. 11c and 11d illustrate perspective views of the vented valve capof FIG. 11 b.

FIG. 12a illustrates a formed stability shim.

FIG. 12b illustrates an example assembly view of a vented valve caphaving a wave spring stability shim.

FIGS. 12c and 12d illustrate perspective views of the vented valve capof FIG. 12 b.

FIGS. 13a through 13c illustrate an inner cap having a stability ring.

DETAILED DESCRIPTION

Preferred embodiments of the present invention will be described hereinwith reference to the accompanying drawings. In the followingdescription, well-known functions or constructions are not described indetail because they may obscure the invention in unnecessary detail.

All documents mentioned herein are hereby incorporated by reference intheir entirety. References to items in the singular should be understoodto include items in the plural, and vice versa, unless explicitly statedotherwise or clear from the text. Grammatical conjunctions are intendedto express any and all disjunctive and conjunctive combinations ofconjoined clauses, sentences, words, and the like, unless otherwisestated or clear from the context. Thus, the term “or” should generallybe understood to mean “and/or” and so forth.

Recitation of ranges of values herein are not intended to be limiting,referring instead individually to any and all values falling within therange, unless otherwise indicated herein, and each separate value withinsuch a range is incorporated into the specification as if it wereindividually recited herein. The words “about,” “approximately,” or thelike, when accompanying a numerical value, are to be construed asindicating a deviation as would be appreciated by one of ordinary skillin the art to operate satisfactorily for an intended purpose. Ranges ofvalues and/or numeric values are provided herein as examples only, anddo not constitute a limitation on the scope of the describedembodiments. The use of any and all examples, or exemplary language(“e.g.,” “such as,” or the like) provided herein is merely intended tobetter illuminate the embodiments and does not pose a limitation on thescope of the embodiments. No language in the specification should beconstrued as indicating any unclaimed element as essential to thepractice of the embodiments.

In the following description, it is understood that terms such as“first,” “second,” “top,” “bottom,” “side,” “front,” “back,” and thelike are words of convenience and are not to be construed as limitingterms. Further, the word “exemplary” means “serving as an example,instance, or illustration.” The embodiments described herein are notlimiting, but rather are exemplary only. It should be understood thatthe described embodiments are not necessarily to be construed aspreferred or advantageous over other embodiments. Moreover, the terms“embodiments of the invention,” “embodiments,” or “invention” do notrequire that all embodiments of the invention include the discussedfeature, advantage, or mode of operation.

A vented fill cap may provide a number of advantages. First, a ventedfill cap should provide an adequate seal while permitting for quickremoval and reconnection, thereby increasing convenience when refillingthe tank. An adequate seal prevents ingression of contaminants into thefuel storage tank. Contaminants, such as water, can lead to the growthof bacteria, corrosion of the tank and system components, and/or causedamage to downstream equipment. Similarly, dirt (or dust) contaminantscan cause premature equipment wear (pumps, nozzles, etc.) as well ascause damage to downstream equipment. Further, an adequate sealmitigates evaporative loss of certain types of fluids, such as gasoline.The reduction of evaporation loss yields economic returns as well asreducing air pollution and hazards.

Second, a vented fill cap should accommodate pump flow rates byadmitting compensatory air into the tank (e.g., a volume of air tooffset the volume of fuel removed) while maintaining a minimal vacuum inthe tank, thereby allowing for rapid removal of fuel from the tank(e.g., with a pump) with the vented fill cap still installed. Thus, avented fill cap can provide appropriate pressure equalization betweenthe tank and the atmosphere, and then reseal after venting excesspressure or drawing in air to relieve the vacuum. To maintain theintegrity of the tank, while prohibiting a perpetual vent to atmosphere,the vented fill cap may be configured to vent at a predeterminedpressure. For example, the vented fill cap may vent at about 1.25 to 1.5psig (pound-force per square inch gauge), while in other aspects, thispressure could be configured to vent at up to about 2.5 psig. Unlikewith vented fuel tank caps employed in automobiles, vented fill caps forstorage tanks must allow for the quick removal of large amounts offluid. For example, fuel transfer pumps can dispense upwards of 30gallons per minute (GPM), which allows for fueling of mobile equipment(e.g., farm vehicles, mobile tanks, etc.) in a reasonable amount of timewithout requiring the removal of the vented fill cap.

Finally, the vented fill cap may be interchangeable betweenmanufacturers, thus enabling them to fit on existing vented fill capbases. As is known to those of skill in the art, a fill cap basegenerally refers to a type of fitting that couples the vented fill capto a bunghole in the top of commonly available fuel storage tanks. Forexample, fuel storage tanks typically employ a two-inch National PipeThread Taper (NPT) bunghole. Further, it is recommended that vented fillcaps are replaced periodically, typically at three-year intervals. Thisensures that gasket materials, which often degrade with time, are stillin a functional condition. Thus, it is desired that vented fill caps beinterchangeable between various manufacturers' fill cap bases,especially in the event that the original cap and base manufacturers areno longer available.

Turning now to the figures, FIG. 1a illustrates an exploded assemblyview of a vented valve cap 100 in accordance with an aspect of thepresent invention, which meets the above objectives. As illustrated, thevented valve cap 100 may comprise a cap cover 102, a pressure spring104, a vacuum spring 106, a valve body 108, a pressure gasket 110, avacuum gasket 112, a vacuum valve 114, and a wire-form keeper 116. Thevarious components of the vented valve cap 100 are genericallyconcentric to one another (sharing the same center point). FIG. 1billustrates a cross-sectional side view of an assembled vented valve cap100, while FIGS. 1c and 1 d illustrate assembly views of the ventedvalve cap's 100 top assembly 200 and bottom assembly 300.

To provide increased lateral stability when installed on a fill capbase, the vented valve cap 100 may further comprise a stability shim118. FIG. 1e illustrates a cross-sectional side view of an assembledvented valve cap having a stability shim 118. The stability shim 118 maybe fabricated from a fuel-resistant material (e.g., a Buna compound)having a hardness of, for example, about 50 to 90 durometer shore A,more preferably about 60 durometer shore A. As illustrated in FIG. 1e ,the stability shim 118 may be installed to lay adjacent the undersidesurface of the cap cover 102. The inner diameter of the stability shim118 may be sized and shaped to result in a slight stretch fit around thecap cover's 102 extruded inner cap's 102 a cylindrical cap body, whichis illustrated as being concentric with the cap cover 102. Thecylindrical cap body may be integral with (e.g., a portion of) the innercap 102 a or a separate component coupled to the inner cap 102 a. Thewidth of the stability shim 118 may approximately the same as, or lessthan, the distance between the inner surface of the securing tab 202 andthe outer surface of inner cap 102 a (e.g., about 0.25 to 0.75 inches,more preferably about 0.35 inches). In such a configuration, the innercap 102 a (and cap cover 102) would be restricted in its movement uponinstallation on a fill cap base, thereby mitigating unwanted play. Wheninstalled, the stability shim 118 provides the user with a degree ofresistance when turning, thereby providing the user an indication that aseal has been formed, and locking the vented valve cap 100 in place. Inaddition, the stability shim 118 also mitigates loosening of the capthat may result from, for example, vibration or use. Figure ifillustrates a perspective view of the underside of the top assemblyhaving a stability shim 118, with the wire-form keeper 116 engaged,while FIG. 1g illustrates an assembly view of a vented valve cap havinga stability shim 118 in accordance with an aspect of the presentinvention. While FIG. 1e illustrates an example stability shim 118, aswill be discussed below, other variations are contemplated, such asstability levers 900, wave spring stability shims, and/or formedstability shims.

FIGS. 2a through 2d and 3a through 3c illustrate the individualcomponents and sub-assemblies of the vented valve cap 100 at variousassembly stages. For illustrative purposes, the stability shim 118,which may be optional or substituted with an alternative shim or tab, isnot illustrated. Specifically, FIGS. 2a through 2d illustrate the topassembly 200, while FIGS. 3a through 3c illustrate the bottom assembly300 (e.g., a valve assembly). As will be described, the top assembly 200generally comprises the cap cover 102 and the wire-form keeper 116,which secures the top assembly 200 to the bottom assembly 300, asillustrated in FIGS. 1c and 1d . When assembled, as will be illustratedbelow, the top assembly 200 slidably engages the bottom assembly 300,thereby permitting vertical movement of the cap cover's 102 bottomassembly 300 relative to the top assembly 200. The bottom assembly 300,on the other hand, may comprise the pressure spring 104, the vacuumspring 106, the valve body 108, the pressure gasket 110, the vacuumgasket 112, and the vacuum valve 114.

In lieu of a wire-form keeper 116, another form of keeper device, suchas a keeper clip 120, may instead be used as illustrated in FIG. 1a .The keeper clip 120 is similar to the wire-form keeper 116 in that itcomprises keeper indentations and secures the top assembly 200 to thebottom assembly 300, but differs in terms of its structure andmanufacture. For example, while the wire-form keeper 116 is formed bybending a wire into a desired shape, the keeper clip 120 may be moldedor stamped from, for example, a fuel-resistant material.

As best illustrated in FIGS. 2a through 2d , the cap cover 102 may befabricated using an inner cap 102 a and an outer cap 102 b. For example,the inner cap 102 a may be welded to the outer cap 102 b at a pluralityof locations (e.g., at the weld points A, as indicated in FIG. 2b ) suchthat it protrudes substantially perpendicularly from the undersidesurface of the cap cover 102. While weld points A are illustrated, othertypes of fastening techniques may be used to form the cap cover 102,including, for example, alternate projection welding patterns, use ofadhesives, stamping techniques, riveting techniques, or another weldmentof various components. Further, the inner cap 102 a and the outer cap102 b may be molded, or otherwise formed into the cap cover 102, from asingle material. For instance, the cap cover 102 may be fabricated froma single material and/or as a single component using three-dimensionalprinting techniques. In certain aspects, the width (i.e., outerdiameter) of the cap cover 102 may be, for example, about 1 to 10inches, more preferably about 3 to 5 inches, and most preferably about 4inches.

In certain aspects, the cap cover 102 may be fabricated from afuel-resistant material (e.g., metal, thermoplastic, or other resin),which may be further resistant to ultraviolet (UV) light. For example,the cap cover 102 (and sub-portions) may be fabricated using ASTM A1008DDS cold rolled carbon steel, which, as discussed below, may be furtherpowder coated. However, the cap cover 102 may be fabricated from one ormore other non-corrosive metallic materials. When a metallic material isnot desirable, an example non-metallic fuel-resistant material includes,for example, BASF Ultramid 8233GHS BK 102.

In a general sense, the outer cap 102 b allows for the cap cover 102 toshield the fill cap base 802 and other valve mechanisms (e.g., thebottom assembly 300) from rain, debris, and/or damage. Further, asecurity hole 102 c may be provided in the outer cap 102 b to functionas a security attachment point, such as a padlock, chain, etc. Thediameter of the security hole 102 c may be, for example, about 0.25 to 1inch, more preferably about 0.25 to 0.75 inch, and most preferably about0.33 of an inch.

The inner cap 102 a may comprise a cylindrical cap body and plurality ofsecuring tabs 202 along the circumference of cylindrical cap body. Thewidth of the inner cap's 102 a cylindrical cap body may be, for example,about 1 to 8 inches, more preferably about 1.5 to 2.5 inches, and mostpreferably, about 2 inches. When assembled, the cylindrical cap body mayperpendicularly protrude about 0.25 to 2 inches, more preferably about0.5 to 1 inch, and most preferably about 0.75 inches from the undersidesurface of the cap cover 102. The width of each of the plurality ofsecuring tabs 202 may be, for example, about 0.125 to 0.875 inches, morepreferably about 0.25 to 0.75 inches, and most preferably about 0.375 to0.5 inches.

That is, a plurality of securing tabs 202 may be provided at the outercircumference of the inner cap 102 a and configured to mate with, orengage, one or more corresponding receiver components on a fill cap base802, or otherwise lock and position the cap cover 102 to a fill cap base802. The plurality of securing tabs 202 may be configured tosubstantially align to a plane defined by the distal end of thecylindrical cap body, but may be adjusted as desired to couple with aparticular fill cap base. For example, as illustrated, two securing tabs202 may be positioned on either side of the inner cap 102 a and spaced180 degrees apart. However, one of skilled in the art would understandin view of the subject disclosure that while two securing tabs 202 areillustrated, other arrangements are possible. The distant between theinner surface of a first securing tab 202 and the inner surface of asecond securing tab 202 that is paced 180 degrees apart may be, forexample, about 1 to 7 inches, more preferably about 2 to 4 inches, andmost preferably about 2.75 inches.

A plurality of slots (e.g., 2 to 5, more preferably about 3 to 4, andmost preferably 3) may be provided on the cylindrical cap body of theinner cap 102 a, the plurality of slots being configured to collectivelyreceive and/or retain the wire-form keeper 116, which secures the bottomassembly 300 to the top assembly 200. Thus, as illustrated, each of saidplurality of slots may receive at least a portion of the wire-formkeeper 116. Specifically, each slot 204 may receive a keeper indentation206 (e.g., an inwardly bent notch segment on said wire-form keeper 116).Thus, installation may be accomplished by spreading the wire-form keeper116 over the cylindrical cap body of the inner cap 102 a; such that eachkeeper indentation 206 is positioned/inserted into a slot 204. Thewire-form keeper 116 may be fabricated from a corrosion-resistantmaterial, such as 15-16 gauge 302 stainless steel. As illustrated, thekeeper indentations 206 may be configured and sized to fit at leastpartially within slots 204.

To provide adequate protection throughout the service life of the ventedvalve cap 100, the cap cover 102, as well as the other components of thevented valve cap 100, may be painted, powder coated, or otherwise coatedwith a protective material. Suitable powder coating materials includethose available from Akzo Nobel Interpon, such as Akzo Nobel Interpon600 product series, which is a polyester-based powder coating forexterior environments that offers light and weather resistance. Tosimulate the appearance of caps that are currently available in themarket, which often have a metal cap with yellow zinc chromate coating,a “soft gold” powder coat color may be chosen.

FIGS. 3a through 3c illustrate the bottom assembly 300. As illustrated,the bottom assembly 300 employs a pressure spring 104 and a vacuumspring 106 to facilitate venting of the vented valve cap 100. Thepressure spring 104 may be fabricated from a corrosion-resistantmaterial, such as 13 gauge 302 stainless steel wire. The diameter of thepressure spring's 104 coil may be maximized with regard to the insidediameter of the valve body 108, thereby allowing maximum stability(e.g., via a larger footprint) and consistency in pressure venting. Thediameter of the pressure spring's 104 coil may be, for example, about 1to 5 inches, more preferably about 1 to 2 inches, and most preferablyabout 1.5 inches, while the vacuum spring's 106 coil may be, forexample, about 0.25 to 1 inches, more preferably about 0.33 to 0.67inches, and most preferably about 0.5 inches. The pressure spring 104may reside at least partially within each of the cylindrical valve bodyportion 608 of valve body 108 and the cylindrical cap body of the innercap 102 a. The pressure spring 104 is configured to impart a force thatbiases the bottom assembly 300 away from said top assembly 200.

The compression rate (i.e., spring constant) of the spring at installedheight, in conjunction with the physical design of the other components,dictates the pressure at which the vented valve cap 100 vents pressure.The compression rate also allows the venting mechanism to properlyfunction in instances when the cap is not properly installed on the fillcap base 802, thereby permitting for some fit deviation. The distal endsof the pressure spring 104 may be turned in toward the center of thecoil so that potentially sharp ends do not hinder the ability ofadjacent components to turn relative to one another upon installation onthe fill cap base 802. The compression spring ends (e.g., pressurespring 104 and vacuum spring 106) may be configured such that they allowfor minimal friction against the cap cover 102 and against valve body108 when rotated. This is notable because the pressure gasket 110 andvalve body 108 assemblies should not rotate relative to the fill capbase 802 when installed. The vacuum spring 106 may be similarlyfabricated from a corrosion-resistant material, such as 302 stainlesssteel. The compression rate of the vacuum spring 106 at installedheight, in conjunction with the physical design of the other components,dictates the point at which vacuum is relieved (i.e., the point at whichthe vacuum valve 114 extends into the tank so as to draw in compensationair). The compression rate of the vacuum spring 106 may be chosen toensure that an adequate seal is present when there is virtually zeropressure in the tank, thereby preventing fuel vapors from escaping tothe atmosphere.

One of skill in the art would appreciate that the compression rate ofthe pressure spring 104 and/or vacuum spring 106 may be adjusted to venta given tank at a desired pressure (or vacuum). For example, to permit ahigher pressure within the tank, the spring constant of the pressurespring 104 may be increased, while the tank may be limited to a lowerpressure by decreasing the spring constant of the pressure spring 104.Similarly, to permit a higher vacuum (negative pressure) within thetank, the spring constant of the vacuum spring 106 may be increased,while the tank may be limited to a lower vacuum by decreasing the springconstant of the vacuum spring 106.

A detailed view of the valve body 108 is illustrated in FIGS. 4a and 4b. The valve body 108, as well as the vacuum valve 114 (discussed below),may be fabricated from a fuel-resistant material (e.g., thermoplastic,or other resin), which may be further resistant to ultraviolet (UV)light. A suitable fuel-resistant material includes, for example, BASFUltramid 8233GHS BK 102. As noted above, the same material may also beused to fabricate the cap cover 102, but the various structuralcomponents of the vented valve cap 100 need not be fabricated from thesame materials.

The valve body 108 may comprise a cylindrical valve body portion 608having a plurality of vent holes 604, and a valve base 606 positioned ata first end of the cylindrical valve body portion 608, and a rib 602positioned at the second end. In certain aspects, the valve body 108 maybe sized and shaped to define the cylindrical valve body portion 608.The outer diameter of the valve body's 108 cylindrical valve bodyportion 608 may be, for example, about 0.5 to 3 inches, more preferablyabout 1.0 to 2.0 inches, and most preferably about 1.66 inches.

As illustrated, a through hole 406 may be positioned at the center ofthe valve base 606 of the valve body 108 to allow the vacuum stem 502 ofthe vacuum valve 114 to protrude through the valve base 606 to the otherside, thereby allowing assembly of the vacuum valve 114 to the valvebody 108 via the vacuum spring 106 (as illustrated in FIG. 6a ). Thethrough hole 406 may be slip fit with regard to the vacuum stem 502 ofthe vacuum valve 114 so as to mitigate unwanted lateral movement, whilepermitting vertical movement (e.g., when venting).

As illustrated in FIGS. 5a through 5c , vacuum valve 114 generallycomprises a vacuum base (e.g., disk-shaped base 508) and a vacuum stem502 perpendicularly positioned at the center of said disk-shaped base508. The vacuum base is moveable between a first position and a secondposition, wherein the vacuum base prevents flow through the half-moonshaped vent slots 408 in the first position and permits flow through thehalf-moon shaped vent slots 408 in the second position, the vacuum basebeing biased in the first position by a vacuum spring 106.

The disk-shaped base 508 may have a diameter of about 0.5 to 3 inches,more preferably about 1 to 2 inches, and most preferably about 1.33inches, while the vacuum stem 502 may have a diameter of about 0.25 to 1inches, more preferably about 0.25 to 0.5 inches, and most preferablyabout 0.33 inches. When assembled, the vacuum gasket 112 slips over thevacuum stem 502, which functions as a spring support, to lay flushagainst the top surface of the disk-shaped base 508. To mitigateunwanted movement, the inner diameter of the vacuum gasket 112 may beslip fit to the vacuum stem 502 on the vacuum valve 114, with an outerdiameter about equal to that of the disk-shaped base 508. The pressuregasket 110 and vacuum gasket 112 are configured to interact with theirmating parts and sealing surfaces. Each of said pressure gasket 110 andvacuum gasket 112 may be fabricated from a fuel-resistant flexiblematerial. Examples of fuel resistant materials include fuel-resistantNitrile rubber (also known as buna rubber), fluoroelastomer materials(e.g., a viton compound), etc. The fuel-resistant flexible material'shardness may be, for example, about 50 to 100 durometer shore A, morepreferably about 70 durometer shore A.

As noted above and illustrated in FIGS. 6a through 6d , a rib 602 may bepositioned at the top edge (e.g., a second end) of the valve body 108,on the body's cylindrical cap body's outside diameter. The rib 602 maybe sized such that it interferes with the wire-form keeper 116 (wheninstalled), thus allowing the top assembly 200 and the bottom assembly300 to remain assembled while the pressure spring 104 is in a constantstate of compression. In other words, the rib 602 may push past thewire-form keeper's 116 contact points, enabling snap together assembly.Similarly, the top assembly 200 may be removable from the bottomassembly 300 without requiring dismantling of the vented valve cap 100or resulting in damage to the vented valve cap 100. For example, the topassembly 200 may be pulled away from the bottom assembly 300 until therib 602 pushes past the wire-form keeper's 116 contact points. Thediameter of the rib 602 may be, for example, about 0.55 to 3.5 inches,more preferably about 1.1 to 2.2 inches, most preferably, about 1.85inches, while the diameter of the valve base 606 may be, for example,about 1.0 to 4.0 inches, more preferably about 1.5 to 2.5 inches, mostpreferably, about 2.1 inches. As best illustrated in FIG. 6d , thedisk-shaped base 508 and the valve base 606 are arranged substantiallyconcentric and parallel to one another, the disk-shaped base 508 beingmoveable between a first position and a second position.

The rib's 602 geometry allows for the wire-form keeper 116, wheninstalled on a cap cover 102, to be pushed onto the valve body 108easily. This aids in assembly by allowing the wire-form keeper 116 to bepreinstalled on the inner cap 102 a of the cap cover 102. In operation,the valve body 108 and the cap cover 102 may be pushed together,expanding the wire-form keeper 116 as it travels over the rib 602 thenallowing it to contract around the main valve body's 108 cylindricalvalve body portion 608 (just under the rib 602), yielding a fullyassembled vented valve cap 100. More specifically, in order to assemblethe vented valve cap 100, as best illustrated in FIG. 1c , the user needonly apply sufficient force to override the pressure spring's 104 force,which allows the angular surface of the valve body's 108 rib 602 todeflect the wire-form keeper 116, and lock the bottom assembly 300 andtop assembly 200 into assembled vented valve cap 100. As illustrated,the three-point contact of the wire-form keeper 116 allows the bottomassembly 300 to rotate freely.

As illustrated, a plurality of vent holes 604 may be provided throughthe outside of the valve body 108 to allow the passage/transfer of gas(e.g., air) when there is a significant vacuum in the tank, andsignificant compensatory air is required. The cumulative area of thevent holes 604 may exceed the cumulative area of half-moon shaped ventslots 408 (serving as a vent hole) on the valve base 606 of the valvebody 108 so as to maximize vent flow through the vented valve cap 100.Each of the plurality of vent holes 604 (e.g., as illustrated, 6 ventholes 604) may have a diameter of, for example, about 0.1 to 0.5 inches,more preferably about 0.225 inches (i.e., about 0.96 square inches). Thediameter of the holes may be adjusted based upon the number of ventholes 604. That is, if fewer vent holes 604 are provided, the diameterof each vent hole 604 may be increased to allow for a commensurateamount of air flow. Conversely, if a greater number of vent holes 604are provided, the diameter of each vent hole 604 may be decreased.

The cumulative area of these half-moon shaped vent slots 408 has beenmaximized to allow a maximum volume of air to flow through the valvebody 108, while maintaining roughly 7.3 inches of water of vacuum in thetank under maximum fluid withdrawal conditions. A small circular ridge610 may be provided on the valve base 606 of the valve body 108 toprovide an increased seal with the vacuum gasket 112. The small circularridge 610 may be about 1.2 inches in diameter (e.g., when used with avented fill cap configured to couple with a 2 inch bunghole) andcentered on the through hole 406 in the center of the valve body's 108valve base 606. By using a small circular ridge 610 in thisconfiguration, the force per square unit of area at the point of contactbetween the vacuum gasket 112 and the valve body 108 is increased byminimizing the point of contact's surface area. Thus, such a ridgefeature and radius improves poor seal integrity associated with a lowcompression spring rote used in vacuum relief function. In certainaspects, additional ribs may be provided at the other seal points. Forexample, a small circular ridge (or the like) may be provided on thevalve body 108 between the underside of the valve body 108 and thepressure gasket 110.

As illustrated in FIG. 6d , for example, a circular protrusion 612(e.g., a protruding ring axially center with the vented valve cap 100and valve body 108) may protrude from the valve base 606 of the valvebody 108. The circular protrusion 612 may be provided with an undercutto allow for installation of the pressure gasket 110. The circularprotrusion 612 may have an outer diameter of about 0.6 to 3.2 inches,more preferably about 1 to 2 inches, most preferably, about 1.6 inches,and an inner diameter of about 0.5 to 3.0 inches, more preferably about1 to 2 inches, most preferably, about 1.33 inches. As illustrated, thepressure gasket's 110 inside diameter may be smaller than the outsidediameter of the circular protrusion's 612 undercut area 614. Duringassembly, the pressure gasket 110 may be stretched around the outsidediameter of this circular protrusion 612 and into the undercut area 614.Thus, when installed, the pressure gasket 110 may be captured betweentwo surfaces of the valve body 108. The chamfer on the surface of thecircular protrusion 612 may be further configured (e.g., angled) to aidin this assembly process.

As illustrated in FIGS. 7a and 7b , the distal end 500 of the vacuumstem 502 may be configured to accept the torsional end 106 a of thevacuum spring 106. Indeed, the vacuum spring 106 may be provided with atorsional end 106 a to allow for a simple “push and turn” assembly ofthe vacuum spring 106 to the vacuum valve 114. Further, a small kick 600may be provided at the distal end 500 of the vacuum stem 502 to ensurethat the torsional end 106 a of the vacuum spring 106 does not disengagefrom the vacuum valve 114 through irregular use or handling. Inoperation, as best illustrated in FIG. 7b , a flat portion of the vacuumspring's 106 torsional end 106 a may be inserted at step 1 into a slit506 at the end of the vacuum stem 502, upon insertion, at step 2, thevacuum spring 106 may be compressed and rotated (e.g., 90 degrees, or a“quarter-turn” installation) such that, at step 3, the flat end of thevacuum spring 106 is received, and substantially secured (e.g., via aforce imparted by said vacuum spring 106), within a notch 506 at thedistal end 500 of the vacuum stem 502. A spur may be included ontorsional end 106 a to maintain the vacuum spring's 106 position duringoperation (e.g., when fully compressed). In certain aspects, however, ane-clip 702 may be provided at the distal end 500 of the vacuum stem 502to secure the vacuum spring 106. FIGS. 7c and 7d illustrate an exemplaryarrangement for securing the vacuum spring 106 using an e-clip 702.Thus, the distal end 500 of the vacuum stem 502 may alternatively employa groove 704 sized and shaped to receive the e-clip 702 (e.g., above theend of the vacuum spring 106), as best illustrated in FIG. 7d . In suchan arrangement, the vacuum spring 106 need not employ a torsional end.

FIGS. 8a, 8b, and 8c illustrate an example of a vented valve cap 100coupled to a tank 804 under three exemplary pressure conditions. Forclarity, the cap cover 102 of the vented valve cap 100, which wouldcouple to the fill cap base 802, has been omitted from the figures so asto avoid visual obstruction of the other components. Further, asillustrated, and as explained above, the vented valve cap 100 may coupleto the tank 804 via a fill cap base 802 that couples the vented valvecap 100 to a bunghole in the tank 804. In certain aspects, such as whenremovable cap functionality is not needed, the vented valve cap 100 andthe fill cap base 802 may be constructed as a single component toprovide venting functionality to a given tank. In such a situation, forexample, the cap cover 102 may be fixedly and nonremovably coupled withthe fill cap base 802. Finally, in certain aspects, the fill cap base802 and the tank 804 may be provided as a single apparatus (e.g., thefill cap base's 802 cap attachment elements may be formed as part of, orwelded to, the tank 804).

The wire-form keeper 116, valve body 108, pressure spring 104 and capcover 102 may be configured to allow free rotation of the assembly uponinstallation to a fill cap base 802. When installed upon a fill cap base802, the cap cover 102 is pressed into position (e.g., downward, ortoward the tank), which compresses the pressure spring 104. This allowsthe securing tabs 202 on the cap cover 102 to move past correspondingprotrusions on the fill cap base 802. Once the securing tabs 202 arepast these protrusions, the cap cover 102 can be rotated (e.g.,clockwise) into its appropriate position. When rotating the cap cover102, it is preferable to require minimal resistance within the assemblyto make installation easy. However, other means of attaching the capcover 102 to the fill cap base 802 are possible. For example, the capcover 102 may be at least partially threaded and configured to couplewith corresponding threading on the fill cap base 802. In such anembodiment, holes may be provided through the threaded portion on thecap cover 102 to facilitate venting, or, in the alternative, gaps may beprovided between threaded tabs on the cap cover 102.

The vented valve cap 100 of FIG. 8a is illustrated as being coupled to atank 804 under pressure equalization. That is, having zero gaugepressure between the atmosphere 806 and the pressure within the tank804. As illustrated, because pressure equalization exists betweenatmosphere 806 and the tank 804, the vacuum valve 114 with vacuum gasket112 installed is held against the underside of the valve body 108 by thevacuum spring 106. The vacuum spring 106 may be retained on the vacuumvalve 114 by its torsional end 106 a and the mating feature on thevacuum valve 114. The vacuum spring 106 may be configured with acompression rating such that the vacuum spring 106 provides sufficientforce to form a seal in the assembly when there is no vacuum or pressurepresent, but allows for the seal to break in the presence of minimalvacuum. The valve body 108, with pressure gasket 110 installed, is heldagainst a top surface of the fill cap base 802 by the pressure spring104. The pressure spring 104, upon installation on the fill cap base802, is compressed by the cap cover 102 adequately to form a seal of upto, for example, 1.25-1.5 psig in the tank.

FIG. 8b illustrates the vented valve cap 100 as being coupled to a tank804 having a positive gauge pressure within the tank 804 (with referenceto the atmosphere 806). For example, the positive gauge pressure may be,for example, 1.25-1.5 psig, which causes the vented valve cap 100 tovent the excess gas from the tank 804. More specifically, the force(direction F) of the pressure in the tank 804 is exerted upon theunderside of the vacuum valve 114, valve body 108, and surface area ofthe pressure gasket 110 within the opening of fill cap base 802. In thisstate, the pressure spring 104 compresses, thereby breaking the sealbetween the fill cap base 802 and the pressure gasket 110. Upon reliefof excess pressure (indicated in the figure as EP) in the tank 804, thepressure spring 104 extends and substantially reforms the seal betweenthe pressure gasket 110 and the fill cap base 802. Upon pressureequalization between atmosphere 806 and the tank 804 (or achieving apredetermined targeted tank pressure/vacuum), the vacuum spring 106extends and reforms the seal between the vacuum gasket 112 and the valvebody 108 (as illustrated in FIG. 8a ). That is, after pressureequalization between atmosphere and the tank, the vacuum spring 106 mayextend and reseal at a targeted pressure above 0 psig. For example,after venting, 0.8 psig may remain in the tank relative to theatmosphere. This operation prevents the tank 804 from venting to openatmosphere 806 until a sufficient pressure is again achieved. Thus, thepoint in which the vented valve cap 100 is sealed in each direction maybe dictated by the spring ratings of the pressure spring 104 and vacuumspring 106, which in turn are guided by the desired (e.g., targeted)tank pressure/vacuum, which need not be 0 psig relative to theatmosphere.

FIG. 8c illustrates the vented valve cap 100 as being coupled to a tank804 having a negative gauge pressure (i.e., a vacuum) within the tank804 (with reference to the atmosphere 806). For example, the negativegauge pressure may be, for example, −0.08 psig, which causes the ventedvalve cap 100 to vent or draw atmospheric air from the atmosphere 806into the tank 804. Indeed, a nominal gauge pressure from the atmosphere806 working against the vacuum valve 114 (direction F) causes the vacuumspring 106 to compress, thereby breaking the seal between the vacuumgasket 112 and the valve body 108. This operation allows forcompensatory air (indicated in the figure as CA) from the atmosphere 806to enter the tank 804 to equalize the pressure. Upon pressureequalization between atmosphere 806 and the tank 804 (or achieving apredetermined targeted tank pressure/vacuum), the vacuum spring 106extends and substantially reforms the seal between the vacuum gasket 112and the valve body 108 (as illustrated in FIG. 8a ). A maximum “flowrating,” which relates to the maximum amount of volume to be removedfrom the tank 804 in a given period of time, may be, for example, 30 GPMor more. Because the half-moon shaped vent slots 408 maximize theavailable air flow, the vented valve cap may facilitate a flow that ismuch higher than 30 GPM. Thus, the vented valve cap 100 can facilitatehigher flow rates vis-à-vis existing fill caps.

FIG. 9a illustrates an inner cap 102 a employing a stability lever 900,which may be used as a first alternative to stability shim 118 of FIGS.1e through 1g . FIG. 9b illustrates an example assembly view of a ventedvalve cap having an inner cap 102 a having a stability lever 900, whileFIGS. 9c and 9d illustrate perspective views of the vented valve cap ofFIG. 9b . As illustrated, a plurality of stability levers 900 may beused to provide increased lateral stability when installed on a fill capbase 802. The outwardly oriented plurality of stability levers 900 maybe spaced around the circumference of the inner cap 102 a. For example,one stability lever 900 may be positioned opposite another stabilitylever 900, as illustrated in Figured 9 a, although additional stabilitylevers 900 may be used. For example, 3 to 6 stability levers 900 may bedistributed around the circumference of the inner cap 102 a. Thestability lever 900 may be stamped from the same material used to formthe inner cap 102 a and the tab portion bent outward or, in thealternative, a piece of material may be fused or otherwise coupled tothe outer surface of the inner cap 102 a through, for example, alternateprojection welding patterns, use of adhesives, stamping techniques,riveting techniques, or another weldment of various components. Incertain aspects, a set of stability levers 900 may be provided at eachlocation. Such an arrangement is illustrated in FIGS. 10a through 10d .Specifically, FIG. 10a illustrates an inner cap 102 a having a set ofstability levers. FIG. 10b illustrates an example assembly view of avented valve cap having an inner cap 102 a having a set of stabilitylevers 900, while FIGS. 10c and 10d illustrate perspective views of thevented valve cap of FIG. 10 b.

FIG. 11a illustrates an inner cap 102 a employing a wave springstability shim 1100, which may be used as a second alternative tostability shim 118 of FIGS. 1e through 1g . FIG. 11b illustrates anexample assembly view of a vented valve cap having a wave springstability shim 1100, while FIGS. 11c and 11d illustrate perspectiveviews of the vented valve cap of FIG. 11b . As illustrated in FIGS. 11cand 11d , the wave spring stability shim 1100 may be installed to layadjacent the underside surface of the cap cover 102. The inner diameterof the wave spring stability shim 1100 may be sized and shaped to fitaround the cap cover's 102 extruded inner cap's 102 a cylindrical capbody (e.g., the main cylindrical portion). The wave spring stabilityshim 1100 may be fabricated from a pre-hardened flat wire with wavesadded to yield a spring effect. The waves may be added through a processcalled on-edge-coiling. During this process, the number of turns andwaves can be adjusted to accommodate stronger force or meet specificrequirements. The wave spring stability shim 1100 offers a number ofadvantages over cupped spring washer (also known as a Bellevillewasher). For example, the axial space can be reduced by 50%, therebyresulting in a significant reduction in weight and production cost.Further, the load in an axial direction is 100% transferable. Finally, awave spring stability shim 1100 enables a higher thrust load within thelimited axial space because only elements of the wave spring stabilityshim 1100 need to be adjusted (e.g., the size of the wire, the number ofwaves, the height of waves, and the number of turns) to accommodate sucha high thrust load.

FIG. 12a illustrates an inner cap 102 a employing a formed stabilityshim 1200, which may be used as a third alternative to stability shim118 of FIGS. 1e through 1g . FIG. 12b illustrates an example assemblyview of a vented valve cap having a formed stability shim 1200, whileFIGS. 12c and 12d illustrate perspective views of the vented valve capof FIG. 12b . As illustrated in FIGS. 12c and 12d , the formed stabilityshim 1200 may be installed to lay adjacent the underside surface of thecap cover 102. The inner diameter of the formed stability shim 1200 maybe sized and shaped to fit around the cap cover 102's extruded innercap's 102 a cylindrical cap body. In certain aspects, the formedstability shim 1200 may be fabricated from a fuel-resistant material(e.g., metal, thermoplastic, or other resin), which may be furtherresistant to ultraviolet (UV) light. For example, the formed stabilityshim 1200 may be fabricated from one or more non-corrosive metallicmaterials. The cross sectional profile of the formed stability shim 1200is generally C-shaped, effectively defining two stacked rings 1204spaced from one another by a perpendicular connector section 1208. Theformed stability shim 1200 may be fabricated from a single material, oras two separate components that are coupled together as a seam. Forexample, the stacked rings 1204 may be separately formed and joined toone another along a seam 1206. Each stacked ring 1204 may be providedwith a plurality of notches 1202 along the circumference, therebyincreasing flexibility and adjusting the force. The number and size ofthe notches 1202 may be adjusted to meet specific requirements. FIGS.13a through 13c illustrate an inner cap 1300 having a stability ring1302. The stability ring 1302 and the one or more securing tabs 202 maybe fabricated as a single component.

While the forgoing has been described as applied to fuel tanks,specifically, fuel storage tanks, one of skill in the art wouldrecognize that the venting technology taught herein may be employed withother applications where venting of tank or system is desired, such assteam tanks, and other fluid tanks, such as those employed by breweriesand distilleries.

The above-cited patents and patent publications are hereby incorporatedby reference in their entirety. Although various embodiments have beendescribed with reference to a particular arrangement of parts, features,and the like, these are not intended to exhaust all possiblearrangements or features, and indeed many other embodiments,modifications, and variations will be ascertainable to those of skill inthe art. Thus, it is to be understood that the invention may thereforebe practiced otherwise than as specifically described above.

What is claimed is:
 1. A venting apparatus comprising: a cap coverhaving a cylindrical cap body concentric with, and protrudingsubstantially perpendicularly from, an underside surface of the capcover; a bottom assembly slidably engaged with, and concentric to, thecap cover, wherein the bottom assembly is sized and shaped to at leastpartially reside within the cylindrical cap body, the bottom assemblyhaving a vacuum valve slidably engaged with a valve body, wherein thevacuum valve and the valve body are arranged substantially concentric toone another, the vacuum valve being moveable between a first positionand a second position, wherein the vacuum valve prevents flow throughthe valve body in the first position and permits flow through the valvebody in the second position; a vacuum spring to bias the vacuum valve inthe first position; and a pressure spring residing at least partiallywithin each of the valve body portion and the cylindrical cap body,wherein the pressure spring is configured to impart a force that biasessaid bottom assembly away from said cap cover.
 2. The venting apparatusof claim 1, further comprising a keeper device to engage said valve bodyand said cylindrical cap body, thereby slidably securing the bottomassembly to the cap cover.
 3. The venting apparatus of claim 1, whereinthe vacuum valve comprises a vacuum base and a vacuum stemperpendicularly positioned on said vacuum base.
 4. The venting apparatusof claim 3, wherein the valve body comprises (1) a cylindrical valvebody portion having a first vent hole and (2) a valve base having asecond vent hole and a through hole to receive the vacuum stem, whereinthe vacuum base and the valve base are arranged substantially concentricand parallel to one another such that the vacuum base prevents flowthrough the second vent hole in the first position and permits flowthrough the second vent hole in the second position, the vacuum basebeing biased in the first position by the vacuum spring.
 5. The ventingapparatus of claim 1, wherein the valve body comprises a slot and thekeeper device comprises an indentation to engage the slot.
 6. Theventing apparatus of claim 1, wherein the cap cover further comprises asecuring tab to engage a fill cap base.
 7. The venting apparatus ofclaim 6, wherein the pressure spring is configured to impart a sealingforce that forms a seal between the bottom assembly and the fill capbase when the cap cover engages the fill cap base, wherein the bottomassembly is configured to move toward said cap cover when a positivepressure at the fill cap base overcomes the sealing force, therebybreaking a seal between the bottom assembly and the fill cap base. 8.The venting apparatus of claim 1, wherein the vacuum valve is configuredto move to the second position when a negative pressure at the fill capbase overcomes the vacuum spring's force.
 9. The venting apparatus ofclaim 1, further comprising a pressure gasket positioned on the valvebody, the pressure gasket to form an airtight seal between the valvebody and a fill cap base.
 10. The venting apparatus of claim 1, furthercomprising a vacuum gasket positioned on the vacuum valve, the vacuumgasket to form an airtight seal between the vacuum valve and the valvebody.
 11. The venting apparatus of claim 1, further comprising astability shim positioned on the underside surface of the cap cover,whereby the stability shim mitigates lateral movement of the ventingapparatus when installed upon a fill cap base.
 12. The venting apparatusof claim 3, wherein the vacuum stem passes through the vacuum spring,the vacuum stem being configured to secure an end of the vacuum springat the vacuum stem's distal end.
 13. A fuel cap comprising: a topassembly having a cap cover and a cylindrical cap body, the cylindricalcap body protruding substantially perpendicularly from an undersidesurface of the cap cover; a bottom assembly slidably engaged with, andconcentric to, the top assembly, the bottom assembly having a vacuumvalve operatively coupled with a valve body; a keeper device to slidablysecure the bottom assembly to the top assembly, wherein the bottomassembly is sized and shaped to at least partially reside within thecylindrical cap body; and a pressure spring to impart a force thatbiases said bottom assembly away from said top assembly.
 14. The fuelcap of claim 13, wherein the vacuum valve is moveable between a firstposition and a second position, wherein the vacuum valve prevents flowthrough the valve body in the first position and permits flow throughthe valve body in the second position.
 15. The fuel cap of claim 14,further comprising a vacuum spring to bias the vacuum valve in the firstposition.
 16. A venting apparatus comprising: a cap cover, the cap coverhaving a cap cover and a cylindrical cap body, the cylindrical cap bodyprotruding substantially perpendicularly from an underside surface ofthe cap cover; a bottom assembly slidably engaged with, and concentricto, the cap cover, the bottom assembly having a vacuum valve operativelycoupled with a valve body, wherein the valve body comprises acylindrical valve body portion, the cylindrical valve body portion sizedand shaped to reside at least partially within the cylindrical cap body;and a pressure spring, the pressure spring residing at least partiallywithin each of the cylindrical valve body portion and the cylindricalcap body, wherein the pressure spring is configured to impart a forcethat biases said bottom assembly away from said cap cover.
 17. Theventing apparatus of claim 16, wherein the vacuum valve is moveablebetween a first position and a second position, wherein the vacuum valveprevents flow through a vent hole in the first position and permits flowthrough the vent hole in the second position, the vacuum valve beingbiased in the first position by a vacuum spring.
 18. The ventingapparatus of claim 16, wherein the venting apparatus is configured toengage a fill cap base, the bottom assembly being configured to movetoward said top assembly when a positive pressure at the fill cap baseovercomes the pressure spring to break a seal between the bottomassembly and the fill cap base.
 19. The venting apparatus of claim 17,wherein (1) the vacuum valve comprises a vacuum base and a vacuum stemperpendicularly positioned on said vacuum base, and (2) the valve bodycomprises a valve base at a first end of said cylindrical valve bodyportion, the valve base having a second vent hole and a through hole toreceive the vacuum stem
 20. The venting apparatus of claim 19, whereinthe vacuum valve is configured to move to the second position when anegative pressure at a fill cap base overcomes the vacuum spring'sforce, thereby permitting flow through the first vent hole and thesecond vent hole.